Evacuation system



United States Patent 3,137,124 EVACUATION SYSTEM George W. Borchers, Houston, Tex., assignor to Nordberg Manufacturing Company, Milwaukee, Wis., a cor- {aeration of Wisconsin Filed Jan. 18, 1962, Ser. No. 167,038 9 Claims. (Cl. 60-16) when it is not being supplied with starting air.

Another object is a method of the above type in which the vacuum in the crankcase is used to create or set up the vacuum in the starting air header.

Another object is a method of'the above type which may be used on two cycle or four cycle engines, oil, dual fuel, gas or otherwise.

Other objects will appear from time to time in the ensuing specification and drawings in which a schematic of the invention is shown.

In the drawings, an engine is indicated generally at 16 and it should be understood that it may be any type of engine, for example two or four cycle, diesel, dual fuel or gas, in line, V, radial or otherwise. The engine may have a conventional drive shaft 12, a crankcase 14, an air header 16 for starting air, and another header 18 which may be considered to be either the inlet or the exhaust header, depending upon which side of the engine you are looking at. In a conventional manner, the starting air header 16 is connected to a source of starting air, indicated generally at 20, through a line 22 controlled by a valve 24. In a conventional manner, the valve 24 is operated to supply high pressure air to the starting air header to get the engine started. I have not shown the starting air valves leading to the cylinders or any of the other conventional operating mechanism concerned with the starting air system.

After the engine is starting and gets running, quite high pressures are developed during combustion in the cylinder. This will cause, from time to time, some of the gases to be forced back through the starting air valves into the starting air header. This occurs while the engine is running. Since the starting air header is not operating, it is static, and the combustion gases leaking by the starting air valves will merely collect and condense in the starting air header.

Further, air from the starting air source is notoriously moist. At any given time, other than during starting, there is a lot of moisture in the starting air header. The combustion gases leaking back through the starting air valves will condense and mix with this moisture in the starting air header which results in a quite acid, corrosive mixture. The result is that the valves, rings, seals and other parts connected to and around the starting air header will be corroded and eaten away rapidly, which results in the annoyance of having to replace them quite frequently. i

One of the important points of my invention is to maintain a vacuum in the starting air header while the engine is running or other than during starting. In the particular form shown in the drawings, I do this by con meeting a line 26 between the starting air header 16 and the crankcase vacuum system. This normally takes the "ice form of a line 28 connected to the crankcase with an oil separator 30 and a blower 32. The blower 32 draws air from the crankcase through the oil separator 30 where the oil is removed. I prefer to connect my special line 26 after the oil separator 30, in other words, between the oil separator and the blower. But it might be otherwise. In any event, the line 28 is under vacuum since the blower 32 maintains a vacuum in the crankcase. Thus, the line 28 may be used to communicate a vacuum to the starting air header 16. The blower may be crankshaft driven, or driven by a separate electric motor, or otherwise.

Line 26 may be controlled by a valve 34 which is normally open, but is closed by an air motor 36, connected to the starting air header by a line 38. Thus, when the starting air header 16 is under pressure from the high pressure air source 20, the air motor 36 will close valve 34 to prevent the high pressure starting air from flowing to line 28 between the oil filter and the crankcase vacuum blower. Otherwise, however, valve 34 is normally open.

Since I am communicating a vacuum to the starting air header, I also vent the header to allow a free flow of air through it. I may do this by connecting a check valve 40 to the other end of the header and placing an air filter 42 ahead of it.

The use, operation and function of my invention are as follows:

Basically, I am concerned with preventing corrosion in and around the starting air header. I have found that due to the leakage of combustion gases back through the starting air valves, a quite corrosive mixture will result in the starting air header when the combustion gases mix with the moisture normally found in the starting air. Also, excessive amounts of corrosive condensate maybe condensed from combustion gases without moisture from any other source.

It will be understood that during starting, quite high pressure air is supplied to the starting air header which passes through the starting air valves and moves the pistons up and down, thereby turning the engine over. Once the engine is operating, however, the starting air system is turned off, either manually or automatically, and the starting air header is static. Moisture, however, has and will collect in the starting air header. Thereafter, during normal running of the engine, the high pressure gases will leak back through the starting air valves and will condense and mix with the moisture in the starting air header resulting in a corrosive mixture,

which is hard on the associated seals, rings, valves, etc. 1

By my invention, I maintain a vacuum in the starting air header, except during starting. It should also be understood that the vacuum may be intermittently supplied to the starting air header during running. But in the preferred form, it is far easier to simply supply the vacuum to the starting air header all the time, except during starting.

During starting, high pressure air will be supplied to the starting air header and the check valve 40 will close. At the same time, the air motor 36 closes the otherwise open valve 34. Thus, the starting air header is completely closed and the starting air system will operate in the normal manner. After the engine is started and is running, however, the source of high pressure air will be cut off and the pressure in the starting air header will drop to zero. This allows normally open valve 34 to open, which automatically communicates the crankcase vacuum to one end of the starting air header. This creates a vacuum in the starting air header and, thereafter, check valve 40 will open to let fresh air flow in the other end.

While I have shown the connections at opposite ends of the header, it should be understood that they may be disposed in any suitable arrangement.

For purposes of simplicity and ease of understanding, I have not shown a lot of the other auxiliary mechanism normally found on or associated with an engine. But it should be understood that they may or may not be used, asthe case requires.

The advantage of maintaining a vacuum on the starting air header, other than during starting, is that the 'gas'that leaks by the starting air valves will be drawn off sufficiently rapidly so that it will not condense and collect. Thus, there is no chance for a corrosive mixture to be set up in the starting air header. I thus fully protect the starting air header, the tubes, valves, springs, etc.

In the event that a higher air flow is required or desired in the starting air header to clear it, I may connect the inlet manifold to the starting air header and control it by a manual or automatic valve, shown at 44, so that at the same time that vacuum is working at one end, a controlled amount of positive air pressure may be applied at the other. But this is normally not needed.

While I have shown and described the preferred form and suggested several variations of my invention, it should be understood that suitable additional modifications, changes, substitutions and alterations may be made without departing from the inventions fundamental theme. I, therefore, wish that the invention be unrestricted, except as by the appended claims.

I claim:

1. In an internal combustion engine, a starting air header adapted to be connected to a source of starting air for starting the engine, and means for communicating a vacuum to the starting air header when it is not being supplied with starting air to remove corrosive products that otherwise might collect therein.

2. In an internal combustion engine having a starting air header, means for communicating a vacuum to the starting air header when it is not being supplied with starting air to remove corrosive products that otherwise might collect therein.

3. In an internal combustion engine, having a cylinder, piston and crankcase, a conduit connecting a source of starting air to the cylinder, a blower connected to the crankcase to draw a vacuum therein, a line connected between the starting, airrconduit and in communication with the crankcase vacuum, and a valve controlling the line so that condensate in the starting air conduit may be drawn out by the crankcase vacuum.

4. The structure of claim 3 further characterized in that the valve is pressure operated but normally open so that the crankcase vacuum will be communicated to the starting air conduit at all times except during starting.

5. The structure of claim 3 further characterized by and including an inlet valve connected to the starting air conduit normally closed but constructed to automatically open in response to a vacuum in the starting air conduit to allow fresh air to flow in when the crankcase vacuum is communicated to the starting air header.

6. The structure of claim 3 further characterized in that the engine has an inlet manifold and further including a line and a valve between the inlet manifold and the starting air conduit so that positive pressure from the inlet manifold may be supplied to the starting air conduit to supplement the vacuum communicated to the starting air conduit from the crankcase.

7. A method of operating an internal combustion engine having a starting air header including the step of communicating a vacuum to the starting air header when it is not being supplied with starting air to thereby remove corrosive products that otherwise might collect therein.

'8. The method of claim 7 further characterized by and including the step of automatically venting the starting air header to the atmosphere in response to the vacuum created therein.

9. The method of claim 7 further characterized by and including the step of automatically venting the starting air header to the atmosphere other than during starting.

No references cited. 

1. IN AN INTERNAL COMBUSTION ENGINE, A STARTING AIR HEADER ADAPTED TO BE CONNECTED TO A SOURCE OF STARTING AIR FOR STARTING THE ENGINE, AND MEANS FOR COMMUNICATING A VACUUM TO THE STARTING AIR HEADER WHEN IT IS NOT BEING SUPPLIED WITH STARTING AIR TO REMOVE CORROSIVE PRODUCTS THAT OTHERWISE MIGHT COLLECT THEREIN. 